Check valve



FIG. 1 is an isometric view of the claimed design.

FIG. 2 is a front view of the claimed design.

FIG. 3 is a right side view of the claimed design.

FIG. 4 is a left side view of the claimed design.

FIG. 5 is a rear view of the claimed design.

FIG. 6 is a top view of the claimed design; and,

FIG. 7 is a bottom view of the claimed design.

The broken lines showing the pattern along the circumference of thesurface on the rear view of the check valve form no part of the claimeddesign.

CLAIM The ornamental design for a check valve, as shown and described.